Predicting Infidelity from Precise Personality Sub-Traits

According to data reviewed by C.J.J. van Zyl, author of a study in the journal Personality and Individual Differences (2021), the most common reason for breakups and divorce is infidelity. Betrayal wreaks the greatest damage on trust, striking love at its roots, undoing years of time spent building the relationship, and casting a shadow on the future of shared satisfaction. While many couples weather the injury, many succumb.

Prior research shows that some factors protect against infidelity¹, while others make it more likely². In addition, while for many couples infidelity is a relationship-ending event, for other couples hidden—and sometimes openly secret infidelity—may help stabilize relationships.

The unfaithful personality

Given the crucial importance of trust in any relationship, and the need for exclusivity in monogamous relationships—which remain the most common in spite of a rise in mutually open relationships as a function of “less restrictive" sociosexuality—researchers have taken a keen interest in understanding what personality traits may increase or decrease the likelihood of infidelity.

Van Zyl notes that the majority of research has looked at personality traits. In addition to the “dark triad” (narcissism, Machiavellianism, psychopathy), the Five Factor Model (FFM) or “Big 5” (OCEAN: Openness to Experience, Conscientiousness, Extroversion, Agreeableness and Neuroticism) have been used to study infidelity.

There are consistent associations between infidelity and each of the Big 5 traits. For example, people who cheat in romantic relationships score higher on Neuroticism, Openness to Experience, and Extraversion. They score lower on Agreeableness and Conscientiousness. However, van Zyl reports that some work has shown different findings for Openness and Extraversion. There is more than meets the eye.

From traits to facets

Facets tell a more nuanced story. While work on personality traits is informative, what many do not realize is that each personality trait is made of sub-traits, called facets. Each trait has six facets. For example, Neuroticism is composed of Anxiety, Angry Hostility, Depression, Self-Consciousness, Impulsiveness and Vulnerability (the full facet list is below for the scale used in this study³).

The facet level also shows where different personality models overlap and contrast with one another. For example, neurotic impulsivity and hostility are features of psychopathy, part of the dark triad. Yet, not all neurotic people are psychopathic, and some features of neuroticism, such as self-consciousness, may contrast with psychopathy. Correlations with broad brushstroke personality traits are therefore misleading where facets are likely more precise. This is true for personality research in general, and not just with infidelity.

In order to look in more detail at personality correlates of infidelity, van Zyl conducted a study of 685 young adults in a university setting, the majority of whom were women (79.2 percent), as part of a larger study on risky behavior. Self-report measures included the Basic Traits Inventory for personality and demographics. Participants were asked about infidelity, how many times had they ever cheated on a romantic partner in their lifetime, coded into "yes" or "no" for purposes of this study. Both traits and facets were analyzed using Bayesian inference, leveraging “fuzzy logic” to discern data patterns.

Findings

On the macro level, Openness and Extraversion were associated with a higher chance of lifetime infidelity, while Conscientiousness, Agreeableness and Neuroticism were associated with a lower chance. These results line up with prior findings, with areas of consistency and inconsistency in which Big 5 traits go along with infidelity and which do not. In this case, Neuroticism had a small positive association with infidelity.

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The facet analysis told a more interesting story, however, getting at the underlying predictors of infidelity. In descending order, the strongest facets associated with infidelity were Extroversion’s facet Ascendance (aka Assertiveness, social boldness), and to a much smaller extent Excitement Seeking; the Duty facet of Conscientiousness, increasing faithfulness; and the Affective (emotional) Instability facet of Neuroticism, associated with increased cheating risk. Other facets had weak or absent correlations.

How not to get cheated on

This data is preliminary yet intriguing. There are limitations. First, this is a younger age group, predominantly women. However, at least in this study, controlling for age, gender and other demographic factors did not change which traits and facets predicted infidelity. Furthermore, as a pilot study, infidelity was measured with one basic question, and analyzed as a Yes or No outcome rather than looking at degrees of infidelity over a large span of relationships.

The duration of the relationship was also not reported, but as the average age hovered around the early 20s, relationship durations are shorter, type of relationship is less mature, and personality characteristics are for younger people. While personality is generally stable over the lifespan, some traits do change with time. Classic research (2017), for example, found that conscientiousness and agreeableness increase with age. This could change the infidelity landscape with age.

Regardless, looking at personality on the level of facets is an important step toward a more refined understanding of how personality interacts with decisions and behavior. Personality traits aren't accurate predictors. For example, Assertiveness is the biggest infidelity risk factor for extraverts. Yet not all extraverts are high on assertiveness, so being extraverted is OK in the absence of specific risks.

Likewise for neuroticism, being neurotic overall does not appear to be the issue, but being emotionally unstable is a problem because feelings may shift suddenly from positive to negative, for example, temporarily weakening feelings that keep people from dalliance. For conscientiousness, a less dutiful partner, which relates to ethics and morality, potentially overlapping with dark traits, is more of a risk.

Short of assessing personality at the beginning of a relationship to identify potential cheaters before it's too late to easily uncouple—bear in mind that research (2017) shows that a prior history of infidelity predicts future risk, and people who have been cheated on are more likely to be cheated on again.

If you know that you are attracted to some of the same traits making romantic choices prone to infidelity, especially if it has happened before, it is critical to slow down, consider taking a break from dating, and figure out what the attraction is to people who have more risky personality facets. History does not have to repeat itself, but it tends to do so if unchecked.

Learn more about personality, and personality change:

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